Numerous diseases result from fungal pathogens, including but not limited to fungal pneumonia (caused by species such as Histoplasma capsulatum, Coccidioides immitis, Blastomyces dermatitidis, and Paracoccidioides brasiliensis), opportunistic pulmonary fungal infections (due to, e.g., Candida species, Aspergillus species, Mucor species, and Cryptococcus neoformans) such as invasive aspergillosis, allergic fungal sinusitis, mucormycosis, and fungal keratitis of the skin or eyes. Additionally, numerous fungal species are capable of causing spoilage or mycotoxin contamination of foodstuffs due to infestation occurring prior to harvest, in stored materials such as grain, or during contamination of finished products. For example, the Food and Agriculture Organization has estimated that 25% of the world's crops are affected by mycotoxins each year, with annual losses of approximately 1 billion metric tons of foods and food products (Schmale et al. (2009) Mycotoxins in Crops: A Threat to Human and Domestic Animal Health, The Plant Health Instructor, American Phytopathological Society DOI: 10.1094/PHI-I-2009-0715-01).
In order to lessen the burden of human, animal, and plant fungal pathogens, it is necessary to detect evidence of fungal contamination or infection with high sensitivity. As fungal nucleic acid can be useful as an indicator of fungal contamination or infection, methods for efficient extraction of fungal nucleic acid are particularly desirable. However, standard methods for nucleic acid extraction result in notoriously poor yield when used for samples containing fungal species, particularly filamentous fungal species. Such low yield can be due to recalcitrance of the fungal cell wall to disruption.
Better methods are needed for fungal nucleic acid extraction.